No Evidence That New Bird Flu Passes Between People: Study

THURSDAY, April 25 (HealthDay News) -- A new study is the first
to confirm that the H7N9 bird flu virus is passed from birds to
people. But the study did not find evidence of person-to-person
transmission.

In the study, Chinese scientists provide details about four
cases of human H7N9 infection in the eastern Zhejiang province. All
four patients had been exposed to poultry, either through their
jobs or by visiting poultry markets.

The study authors tested samples taken from 20 chickens, four
quails, five pigeons and 57 ducks at six poultry markets where the
patients were likely to have been. Two of the five pigeons and four
of the 20 chickens tested positive for H7N9, but the virus was not
found in any of the ducks or quails tested.

Then researchers analyzed the genetic makeup of H7N9 viruses
from one of the patients and one of the chickens and found
similarities between the viruses, confirming that the H7N9 virus
can be transmitted from poultry to people, according to the study
published online April 25 in
The Lancet.

The scientists also tracked 385 family members, co-workers and
health care staff who had unprotected contact with the patients.
None of them showed any symptoms of H7N9 infection over 14 days of
follow-up, which suggests that the virus currently cannot be spread
among people.

However, there is evidence that the H7N9 virus has developed
some genetic characteristics that adapt it specifically to
infection in mammals. Further genetic changes might enable the
virus to be transmitted from person-to-person, the researchers
noted.

"Overall, the evidence, in terms of epidemiology and virology, suggests that it is a pure poultry-to-human transmission, and that controlling [the epidemic in humans] will therefore depend on controlling the epidemic in poultry," study co-lead author Kwok-Yung Yuen, of the University of Hong Kong, said in a Lancetnews release.

That would include measures such as temporary closure of live
bird markets, comprehensive programs of surveillance, culling and
segregation of poultry species, and possibly vaccination of
poultry.

World Health Organization (WHO) officials said Wednesday that
they are concerned about the ability of the H7N9 virus to jump from
birds to humans and to infect birds without causing obvious
symptoms, according to the
Associated Press.

"This is definitely one of the most lethal influenza viruses we have seen so far," Dr. Keiji Fukuda, the top influenza expert at WHO, said during a briefing in Beijing. However, a large number of milder cases may also be going undetected, he added. WHO officials investigated the H7N9 cases with Chinese authorities this week, the APreported.

More than 100 people in China have been infected with the H7N9
virus, with most getting seriously sick and more than 20 dying, the
APnoted. The first case in Taiwan was confirmed on
Wednesday, a 53-year-old man who became sick after returning from a
visit to the eastern Chinese province of Jiangsu.

More information

The U.S. Centers for Disease Control and Prevention has more
about the
H7N9 virus.

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.